Back to EveryPatent.com
United States Patent |
5,276,256
|
Niessner
,   et al.
|
January 4, 1994
|
Flameproofed chlorine-and bromine-free molding composition
Abstract
A molding composition containing, based on the total weight of the
composition:
A) at least 40% by weight of at least one halogen-free polycarbonate;
B) 5-40% by weight of at least one halogen-free graft copolymer composed
of;
1) 40-80% by weight of an elastomer with a glass transition temperature
below 0.degree. C., which elastomer is composed of, at least 50% by weight
of a diene or of an at least C.sub.4 -alkyl acrylate, 1-40% by weight of a
halogen-free phosphorus compound of the formula
##STR1##
2) 20-60% by weight of a shell composed of, 40-98% by weight of styrene,
.alpha.-alkylstyrene, nuclear-substituted styrene and/or C.sub.1 -C.sub.8
-alkyl (meth)acrylate, and 2-60% by weight of (meth)acrylonitrile and/or
maleic anhydride;
C) 5-40% by weight of a halogen-free thermoplastic copolymer composed of,
50-95% by weight of styrene, .alpha.-alkylstyrene, nuclear-substituted
styrene and/or C.sub.1 -C.sub.8 -alkyl (meth)acrylates, and 5-50% by
weight of (meth)acrylonitrile and/or maleic anhydride;
D) 1-50% by weight of a halogen-free phosphorus compound of the formula
##STR2##
E) up to 5% by weight of a polytetrafluoroethylene with a median particle
size of 50-2000 nm.
Inventors:
|
Niessner; Norbert (Friedelsheim, DE);
Neumann; Rainer (Mutterstadt, DE);
Ruppmich; Karl (Ludwigshafen, DE);
Seitz; Friedrich (Friedelsheim, DE);
Zeltner; Doris (Roemerberg, DE)
|
Assignee:
|
BASF Aktiengesellschaft (Ludwigshafen, DE)
|
Appl. No.:
|
950499 |
Filed:
|
September 25, 1992 |
Foreign Application Priority Data
Current U.S. Class: |
525/67; 524/140; 524/141; 524/143; 524/504; 524/537; 525/146; 525/287; 525/902; 526/276; 526/277 |
Intern'l Class: |
C08L 051/00 |
Field of Search: |
525/67,146,902,287
524/140,141,143,504,537
|
References Cited
U.S. Patent Documents
4692488 | Sep., 1987 | Kress et al. | 524/139.
|
4883835 | Nov., 1989 | Buysch et al. | 524/504.
|
4920166 | Apr., 1990 | Buysch et al. | 524/141.
|
4925891 | May., 1990 | Kress et al. | 524/139.
|
4931503 | Jun., 1990 | Boutni et al. | 525/67.
|
4983658 | Jan., 1991 | Kress et al. | 525/67.
|
4988748 | Jan., 1991 | Fuhr et al. | 524/141.
|
5061745 | Oct., 1991 | Wittmann et al. | 524/139.
|
5219907 | Jun., 1993 | Niessner | 525/67.
|
Foreign Patent Documents |
3523316 | Jan., 1987 | DE.
| |
Primary Examiner: Kight, III; John
Assistant Examiner: Johnson; Rachel
Attorney, Agent or Firm: Keil & Weinkauf
Claims
We claim:
1. A molding composition containing, based on the total of A to E,
A: at least 40% by weight of at least one halogen-free polycarbonate A
B: 5-40% by weight of at least one halogen-free graft copolymer B composed
of, based on B,
B1: 40-80% by weight of an elastomer B1with a glass transition temperature
below 0.degree. C., composed of, based on B1,
B11: at least 50% by weight of a diene or of an at least C.sub.4 -alkyl
acrylate (B11)
B12: 1-40% by weight of a halogen-free phosphorus compound B12 of the
formula (I)
##STR7##
where R.sup.1 is H or CH.sub.3
R.sup.2 and R.sup.3 are each, independently of one another, halogen-free
C.sub.1 -C.sub.8 -alkyl or halogen-free unsubstituted or substituted
C.sub.6 -C.sub.20 -aryl
X.sup.1, X.sup.2 and X.sup.3 are each O, S, NR (where R is hydrogen or
halogen-free C.sub.1 -C.sub.8 -alkyl) and n is 0 to 10,
B2: 20-60% by weight of a shell B2 composed of, based on B2,
B21: 40-98% by weight of styrene, .alpha.-alkylstyrene, nuclear-substituted
styrene and/or C.sub.1 -C.sub.8 -alkyl (meth)acrylate,
B22: 2-60% by weight of (meth)acrylonitrile and/or maleic anhydride, and
C: 5-40% by weight of a halogen-free thermoplastic copolymer C composed of,
based on C,
C1: 50-95% by weight of styrene, .alpha.-alkylstyrene, nuclear-substituted
styrene and/or C.sub.1 -C.sub.8 -alkyl (meth)acrylates,
C2: 5-50% by weight of (meth)acrylonitrile and/or maleic anhydride,
D: 1-50% by weight of a halogen-free phosphorus compound of the formula
(II)
##STR8##
where R.sup.2, R.sup.3 and R.sup.4 each independently have the
abovementioned meanings of R.sup.2 and R.sup.3,
E: up to 5% by weight of a polytetrafluoroethylene with a median particle
size of 50-2000 nm.
Description
The present invention relates to a chlorine- and bromine-free flameproofed
molding composition. Chlorine- and bromine-free molding compositions based
on ABS or ASA blends with PC (polycarbonate) are disclosed, for example,
in the following publications:
(1) DE-A 35 23 314
(2) DE-A 35 23 316
(3) DE-A 38 19 081
(4) DE-A 38 24 356
(5) DE-A 36 28 904
(6) EP-A 287 895
(7) EP-A 286 965
Employed besides organic phosphates for the flameproofing are fiber-forming
PTFE polymers. Although blends of this type have a good flame-retardant
action, their notched impact strength is inadequate. In addition, the
amount of organic phosphorus compounds needed for classification as UL 94
results in a considerable reduction in the heat resistance. For this
reason, (4) proposes specific phosphates which ensure an increased Vicat
softening point despite the flameproofing being good: these specific
phosphates are, however, not commercially available and are elaborate to
prepare. In addition, blends containing these phosphates still have
insufficient notched impact strength.
Phosphates which have vinyl double bonds are commercially available and
can, according to the manufacturers, be employed for flameproofing.
However, nothing is known about their effect in PC/ABS and PC/ASA blends.
The phosphates employed for flameproofing normally have to have a certain
volatility because, otherwise, they have no flame-retardant properties.
We have now found that chlorine- and bromine-free molding compositions
based on mixtures of ABS or ASA with polycarbonate (PC) are particularly
flame resistant when they contain a halogen-free graft copolymer whose
core (elastomer) contains a vinyl-substituted phosphate which can undergo
free-radical (co)polymerization, besides conventional monomers (either a
diene such as butadiene or isoprene or an alkyl acrylate with at least 4
carbons in the alkyl).
The present invention therefore primarily relates to a flameproofed
chlorine- and bromine-free molding composition with high heat resistance
and good notched impact strength, containing, based on the total of A to
E,
A: at least 40% by weight of at least one halogen-free polycarbonate A
B: 5-40% by weight of at least one halogen-free graft copolymer B composed
of, based on B,
B1: 40-80% by weight of an elastomer B1 with a glass transition temperature
below 0.degree. C., composed of, based on B1,
B11: at least 50% by weight of a diene or of an at least C.sub.4 -alkyl
acrylate (B11)
B12: 1-40% by weight of a halogen-free phosphorus compound B12 of the
formula (I)
##STR3##
where R.sup.1 is H or CH.sub.3
R.sup.2 and R.sup.3 are each, independently of one another, halogen-free
C.sub.1 -C.sub.8 -alkyl or halogen-free unsubstituted or substituted
C.sub.6 -C.sub.20 -aryl
X.sup.1, X.sup.2 and X.sup.3 are each O, S, NR (where R is hydrogen or
halogen-free C.sub.1 -C.sub.8 -alkyl) and n is 0 to 10,
B13: with or without up to 5% by weight of another, crosslinking monomer
B2: 20-60% by weight of a shell B2 composed of, based on B2,
B21: 40-98% by weight of styrene, .alpha.-alkylstyrene, nuclear-substituted
styrene and/or C.sub.1 -C.sub.8 -alkyl (meth)acrylate,
B22: 2-60% by weight of (meth)acrylonitrile and/or maleic anhydride, and
C: 5-40% by weight of a halogen-free thermoplastic copolymer C composed of,
based on C,
C1: 50-95% by weight of styrene, .alpha.-alkylstyrene, nuclear-substituted
styrene and/or C.sub.1 -C.sub.8 -alkyl (meth)acrylates,
C2: 5-50% by weight of (meth)acrylonitrile and/or maleic anhydride,
D: 1-50% by weight of a halogen-free phosphorus compound of the formula
(II)
##STR4##
where R.sup.2, R.sup.3 and R.sup.4 each independently have the
abovementioned meanings of R.sup.2 and R.sup.3,
E: up to 5% by weight of a polytetrafluoroethylene with a median particle
size of 50-2000 nm.
It was surprising that phosphates of the formula (I) when they are included
in the grafting base of the graft copolymer confer a good flame-retardant
action on the blend and, moreover, the blends have high notched impact
strength. Furthermore, the blends have excellent heat resistance and less
of a tendency for the low molecular weight organic phosphate to leach out.
The molding composition preferably contains the following proportions of
the components, in each case based on the total of A+B+C+D+E:
A: 50-85, in particular 60-70% by weight
B: 5-25, in particular 6-15% by weight
C: 5-25, in particular 10-25% by weight
D: 2-15, in particular 5-15% by weight
E: 0.01-2, in particular 0.1-1% by weight
Based on 100 parts by weight of the molding composition according to the
invention composed of A to E it is possible, for example, for up to 50 (in
particular 20) parts by weight of conventional additives F to be present.
Thermoplastic halogen-free aromatic polycarbonates A suitable according to
the invention are those based on diphenols of the formula (II)
##STR5##
where A is a single bond, C.sub.1 -C.sub.3 -alkylene, C.sub.2 -C.sub.3
-alkylidene, C.sub.3 -C.sub.6 -cycloalkylidene, --S-- or --SO.sub.2 --.
Polycarbonates suitable according to the invention as Component A are both
homopolycarbonates and copolycarbonates.
Diphenols of the formula (II) are generally known or can be prepared by
known processes.
The preparation of polycarbonates A suitable according to the invention is
likewise known and can be carried out, for example, with phosgene by the
phasetransfer process or with phosgene by the homogeneous phase process
(the pyridine process), the required molecular weight being obtained in
each case in a conventional manner by an appropriate amount of known chain
terminators. (Concerning polydiorganosiloxanecontaining polycarbonates,
see, for example, DE-A 33 34 782).
Examples of suitable chain terminators are phenol, p-tert.-butylphenol and
long-chain alkyl phenols such as 4-(1,1,3,3-tetramethylbutyl)phenol (cf.
DE-A 28 42 005) or monoalkylphenols or dialkylphenols with a total of 8 to
20 carbons in the alkyl substituents (cf. DE-A 35 06 472) such as
p-nonylphenol, 3,5-di-tert.-butylphenol, p-tert.-octylphenol,
p-dodecylphenol, 2-(3,5-dimethylheptyl)phenol and
4-(3,5-dimethylheptyl)-phenol.
Polycarbonates A suitable according to the invention have relative
viscosities .eta.hd rel of from 1.10 to 1.50, in particular from 1.25 to
1.40. This corresponds to an average molecular weight M.sub.w of about
10,000-200,000; a molecular weight M.sub.w of 20,000-80,000 is preferred.
Examples of suitable diphenols of the formula (II) are hydroquinone,
resorcinol, 4,4'-dihydroxybiphenyl, 2,2-bis(4-hydroxyphenyl)propane,
2,4-bis(4-hydroxyphenyl)-2-methylbutane and
1,1-bis(4-hydroxyphenyl)cyclohexane.
Preferred diphenols of the formula (II) are 2,2-bis(4-hydroxyphenyl)propane
(bisphenol A) and 1,1-bis(4-hydroxyphenyl)cyclohexane.
Suitable polycarbonates A can be branched in a conventional manner,
preferably by incorporating from 0.05 to 2.0 mol %, based on the total of
diphenols employed, of compounds with three or more functional groups, for
example phenolic OH groups.
Preferred polycarbonates are, besides bisphenol A homopolymer, the
copolycarbonates of bisphenol A.
For the purpose of the present invention, halogen-free polycarbonates A
mean polycarbonates assembled from halogen-free diphenols and halogen-free
chain terminators with or without halogen-free branches, but contents in
the low ppm range of hydrolyzable chlorine resulting, for example, from
the preparation of the polycarbonates with phosgene by the phase-transfer
process are not regarded as a halogen content for the purpose of the
present invention. Polycarbonates of this type with ppm contents of
hydrolyzable chlorine are halogen-free polycarbonates for the purpose of
the present invention.
The graft copolymers B are known in principle as ABS or ASA polymers and
are modified according to the invention by the incorporation of
copolymerizable phosphorus compounds in the core (B11).
The specific graft copolymers B are thus assembled from, in each case based
on B, 40-80% by weight of an elastomer component (core) B1 which in turn
is assembled from the abovementioned components and monomers B11-B13
according to the invention, and 20-60% by weight of a shell B2.
Graft copolymer B is in the case of an ASA preferably formed of the core B1
composed of an elastomer-forming acrylate such as butyl acrylate or
2-ethylhexyl acrylate in an amount of at least 50% by weight (based on
B1), 1-40% by weight of the organic phosphorus compound of the formula (I)
and 0.1-5% by weight, based on B1, of a copolymerizable polyfunctional
crosslinking monomer. The structure and preparation of ASA polymers are
described in principle in DE-A 28 26 925, DE-A 31 49 358 and DE-A 34 14
118. If the invention is to be used to prepare corresponding ABS polymers,
on the other hand, the core B1 is composed of, generally, uncrosslinked
diene polymers, i.e. polymers of butadiene or isoprene, which are modified
by copolymerization with the copolymerizable phosphorus compounds (I).
A shell B2 is attached to this core B1 which has been modified according to
the invention, in a conventional manner.
This shell is in each case composed of, in each case based on B2, 50-95% by
weight of styrene, .alpha.-methylstyrene or a nuclear-alkylated styrene
and/or 50-5% by weight of (meth)acrylonitrile, methyl methacrylate or
maleic anhydride.
The graft copolymerization can be carried out in a conventional manner in
solution, suspension or, preferably, emulsion. The soft phase of the graft
copolymer has, in the preferred case of preparation of the rubber and
grafting in emulsion, a median particle diameter (d.sub.50 of the
cumulative mass distribution) of, for example, from 80 to 800 nm. The
graft copolymerization results, as is known, in at least partial chemical
linkage of the polymerizing monomers to the rubber which has already
polymerized, the linkage probably taking place on the double bonds present
in the rubber. The grafting base modified according to the invention does
not differ from known ones in respect of the grafting behavior.
The grafting can also take place in several stages by grafting on first a
portion of the monomers forming the shell and subsequently the remainder.
The rubber is present in the graft copolymer B in the form of at least
partially crosslinked particles with a median particle size of f rom 50 to
700 nm (d.sub.50 of the cumulative mass distribution). Since the original
particle size is smaller, the particles the rubber are partially enlarged
in a conventional manner, e.g. by agglomeration, so that a bimodal
distribution (50-180 nm on the one hand and 200-700 nm on the other hand)
is obtained. However, a large-particle of rubber dispersion can also be
prepared directly by the seed process.
Graft copolymer B can be prepared, for example, by the method described in
DE-C 12 60 135.
In the case of one-stage assembly of the shell B2, a mixture of the
monomers in the required ratio by weight in the range from 90:10 to 65:35
is polymerized in the presence of the elastomer B1 in a conventional
manner (cf., for example, DE-A 28 26 925), preferably in emulsion.
When the shell B2 is assembled in two stages, the 1st stage comprises
20-70%, preferably 25-50%, of the weight of B2. It is prepared using only
monoethylenically unsaturated aromatic hydrocarbons with up to 12 carbons
(B21). The 2nd stage of the shell comprises 30-80%, in particular 50-75%,
of the weight of B2. It is prepared by using mixtures of said
monoethylenically unsaturated aromatic hydrocarbons B21 and
monoethylenically unsaturated monomers B22 in the ratio B21/B22 of from
98:2 to 40:60, in particular 90:10 to 60:40, by weight.
Monomer mixtures which are particularly preferably employed are styrene and
acrylonitrile, .alpha.-methylstyrene and acrylonitrile, acrylonitrile and
methyl methacrylate, and styrene and maleic anhydride.
The amounts of ungrafted copolymers, i.e. corresponding chemically to
Component C, produced in the preparation of the graft copolymer B from the
monomers B21 and/or B22 are assigned to Component B for the purpose of the
present invention.
The conditions for the graft copolymerization should be chosen so that the
resulting particles have sizes of from 60 to 1000 nm (d.sub.50 of the
cumulative mass distribution). Measures to achieve this are known and
described, for example, in DE-C 12 60 135 and DE-A 28 26 925.
Component C
Preferred halogen-free copolymers C are those composed of at least one
monomer from the series comprising styrene, .alpha.-methylstyrene,
alkylstyrene, methyl methacrylate with at least one monomer from the
series comprising acrylonitrile, methacrylonitrile, methyl methacrylate
and maleic anhydride.
Copolymers C are resinous, thermoplastic and rubber-free and are also
called matrix in this connection. Particularly preferred copolymers C are
those of styrene with acrylonitrile, with or without methyl methacrylate,
of .alpha.-methylstyrene with acrylonitrile, with or without methyl
methacrylate, or of styrene and .alpha.-methylstyrene with acrylonitrile,
with or without methyl methacrylate, and of styrene and maleic anhydride.
The halogen-free phosphorus compounds D suitable according to the invention
are likewise known (for example from Ullmann, Enzyklopadie der technischen
Chemie, Vol. 12/1, pages 43 and 136; Beilstein, Vol. 6, page 177).
Examples of phosphorus compounds D suitable according to the invention are
tri(2,6-dimethylphenyl) phosphate, triphenyl phosphate, tricresyl
phosphate, diphenyl 2-ethyl cresyl phosphate, diphenyl cresyl phosphate
and tri(isopropylphenyl) phosphate.
In order to increase the Vicat softening point of the mixtures, it is also
possible to employ mixtures of the abovementioned phosphates with, for
example, triphenylphosphine oxide or tri (2, 6-dimethylphenyl)phosphine
oxide. Also suitable for increasing the Vicat softening point of the
mixtures are the phosphates mentioned in DE-A 38 24 356, such as
diphenyl 4-phenylphenyl phosphate
phenyl di(4-phenylphenyl) phosphate
tri(4-phenylphenyl) phosphate
diphenyl 4-benzylphenyl phosphate
phenyl di(4-benzylphenyl) phosphate
tri(4-benzylphenyl) phosphate
phenyl di[4-(1-phenylethyl)phenyl] phosphate
phenyl di[4-(1-methyl-1-phenylethyl)phenyl] phosphate and
phenyl di[4-(1-phenylethyl)-2,6-dimethylphenyl] phosphate.
The polytetrafluoroethylenes E suitable according to the invention are
polymers with a fluorine content of 65-76% by weight, preferably 70-76% by
weight. Examples include polytetrafluoroethylene,
tetrafluoroethylene/hexafluoropropylene copolymers or tetrafluoroethylene
copolymers with small amounts of fluorine-free copolymerizable
ethylenically unsaturated monomers. Polymers of these types are known.
They can be prepared by conventional processes, for example by
polymerization of tetrafluoroethylene in aqueous medium with a free
radical-forming initiator, for example sodium, potassium or ammonium
peroxydisulfate, under superatmospheric pressure and at up to 200.degree.
C. (for details, see US-C 2 393 967, for example).
Polytetrafluoroethylenes suitable according to the invention have, for
example, a median particle size of 0.05-20 .mu.m, preferably 0.08-10
.mu.m, and a density of 1.2-1.9 g/cm.sup.3. Addition of
polytetrafluoroethylenes reduces or entirely prevents, in particular,
particles dropping off the molding compositions when they are burning.
The aqueous PTFE dispersion can be either absorbed onto the granules in a
fluid mixer or incorporated into a melt of Component C in an extruder with
vent.
It is also possible for emulsions of Component B to be combined with
emulsions of Component F and precipitated using salt solution.
The molding composition can also contain conventional additives F, for
example carbon fibers or glass fibers, in particular.
Glass fibers can be of low or high alkali glass or C glass. They are
preferably treated with a size and an adhesion promoter. Their diameter is
generally from 6 to 20 .mu.m. It is possible to employ both continuous
strands (rovings) and chopped strands with a length of 1-10 mm, preferably
3-6 mm.
Examples of other suitable additives are fillers or reinforcing agents such
as glass beads, mineral fibers, whiskers, alumina fibers, mica, silica
flour, wollastonite etc.; used for a screening action against
electromagnetic radiation are, for example, metal flakes (e.g. aluminum
flakes), metal powders, metal fibers, metal-coated fillers (e.g.
nickel-coated glass fibers) and similar additives.
The molding composition according to the invention can also contain
additives which are typical and customary for polycarbonates, SAN polymers
and graft copolymers based on ASA or ABS or mixtures thereof. Examples of
such additives are dyes, pigments, antistatics, antioxidants and, in
particular, the lubricants which may be necessary for further processing
the molding composition, e.g. the production of moldings.
Additives not specified in the composition according to the invention
(component F) can be added in amounts of up to 80 parts per 100 parts of
the total of Components A to E in the mixture.
In this connection, processing aids and stabilizers are normally used in
amounts below 2%.
Reinforcing agents such as glass fibers, carbon fibers etc. are normally
added in amounts of 5-80% based on the total of A to E.
Preparation of the molding composition
The molding composition according to the invention is prepared by mixing
the components. It may be advantageous for some components to be
previously mixed. It is also possible to mix the components in solution
and to remove the solvent.
Examples of organic solvents suitable for Components A to E are
chlorobenzene, mixtures of chlorobenzene and methylene chloride or
mixtures of chlorobenzene and aromatic hydrocarbons, e.g. toluene.
The solvent mixtures can be evaporated off, for example, in evaporating
extruders.
The mixing of the, for example, dry Components A, B, C, D and E, with or
without F, can take place by all conventional methods. However, Components
A, B, C, D and E, with or without F, are preferably mixed at
200.degree.-320.degree. C. by the components being extruded, kneaded or
rolled together, if necessary after isolation from the solution obtained
in the polymerization or from the aqueous dispersion. The products of the
graft copolymerization (Component B) obtained in aqueous dispersion can be
coagulated, precipitated and partly dehydrated together with Component E,
or mixed directly as dispersions with Component C and then with the
polycarbonate A and Component D, in which case Components B and E are
completely dried during the mixing. It is also possible for the emulsion
of Component E to be poured with degassing in an extruder into a melt of
Component C, and for the other Components A, B and D to be metered in in
the same extruder after the degassing.
Examples of suitable mixing units for the process according to the
invention are conventional tumble mixers or stirrers.
Examples of suitable units for the melt compounding are heated internal
mixers operating batchwise or continuously, screw compounders with axially
oscillating screws, twin screw extruders and heated mixing rolls.
Examples of suitable units for the melt extrusion are single and twin screw
extruders.
The molding composition according to the invention can be processed in ways
conventional for thermoplastics, e.g. by extrusion, injection molding,
calendering, blow molding, compression or sintering; the molding
compositions prepared by the process according to the invention are
particularly preferably used to produce injection moldings for automobile
construction, the building sector, for office machinery, electrical
equipment and household appliances.
The parameters used in this application are determined as follows:
The median particle size and the particle size distribution were determined
from the cumulative mass distribution. The median particle size is in
every case based on weight and was determined using an analytical
ultracentrifuge by the method of W. Scholtan and H. Lange, Kolloid-Z. und
Z. f. Polymere 250 (1972), 782-796. The ultracentrifuge measurement
provides the cumulative mass distribution of the particle diameter in a
sample. It is possible to deduce from this the percentage by weight of the
particles which have a diameter equal to or smaller than a particular
size. The median particle diameter, which is also called the d.sub.50 of
the cumulative mass distribution, is defined as the particle diameter
greater than that of 50% by weight of the particles and smaller than that
of 50% by weight of the particles. The width of the particle size
distribution of the rubber particles is characterized not only by the
d.sub.50 but also by the d.sub.10 and d.sub.90 which are derived from the
cumulative mass distribution and are defined in a similar way to the
d.sub.50 but relate to 10 and 90% of the particles respectively. The
quotient Q
##EQU1##
represents a measure of the width of the particle size distribution.
The notched impact strength a.sub.K in kJ/m.sup.2 was measured by the DIN
53 453 method on spe cimens with dimensions 50.times.6.times.4 mm with a
rectangular notch 1.3 mm deep and 2 mm wide at 23.degree. C.
The Vicat softening point B/50 was determined on specimens of dimensions
50.times.6.times.4 mm by the DIN 53 460 method.
The relative solution viscosity .eta..sub.rel of the polycarbonate employed
was measured in a 0.5% strength solution in methylene chloride at
23.degree. C.
The viscosity number VN of the copolymers C was determined in a 0.5%
strength solution in dimethylformamide at 23.degree. C.
The flameproofing was tested in a vertical burning test as specified by the
Underwriter's Laboratories for assignment to Class UL 94 V-0, V-1 or V-2.
A flameproofed thermoplastic is classed V-0 when the following criteria
are met: none of 5 specimens with dimensions 127.times.12.7.times.1.7 mm
must burn for longer than 10 seconds after two applications of a flame
(height 19 mm) for 10 seconds. The total of the burning times after 10
applications of the flame to 5 specimens must not exceed 50 seconds. There
must be no dripping of flaming particles, nor complete combustion or
glowing combustion persisting for more than 30 seconds. The requirement
for Class UL 94 V-1 is that the total of the burning times after 10
applications of a flame to the 5 specimens does not exceed 250 seconds.
Glowing combustion must not persist for more than 60 seconds. The other
criteria are identical to those mentioned above. The requirements for
Class V-2 are identical to those for UL 94 V-1 except that there is
dripping of flaming particles.
The products described hereinafter were used to prepare molding
compositions according to the invention and compositions for comparative
tests.
The product of the formula Ia
##STR6##
which is obtainable under the name MR.sup.260 from Daihachi Inc. was used
as phosphorus compound B12.
Component A
A commercial polycarbonate based on bisphenol A with a relative solution
viscosity of 1.30 was employed as Component A.
Component B
For comparison, a graft copolymer without polymerizable phosphate was
prepared as product B-1 as follows:
1.5 parts of a poly(butyl acrylate) latex were mixed with 50 parts of water
and 0.1 part of potassium persulfate and then, over the course of 3 hours,
on the one hand a mixture of 49 parts of butyl acrylate and 1 part of
tricyclodecenyl acrylate, and on the other hand a solution of 0.5 part of
the sodium salt of a C.sub.12 -C.sub.18 -paraffinsulfonic acid in 25 parts
of water were run in at 60.degree. C. Polymerization was continued for 2
hours after the addition was complete. The resulting latex of the
crosslinked poly(butyl acrylate) had a solids content of 40%. The median
particle size (based on weight) was found to be 430 nm. The particle size
distribution was narrow (Q=0.1).
150 parts of this latex were mixed with 20 parts of styrene and 60 parts of
water and stirred while a further 0.03 part of potassium persulfate and
0.05 part of lauryl peroxide were added, and then the mixture was heated
at 65.degree. C. for 3 hours. The dispersion obtained from this graft
copolymerization was then polymerized with 20 parts of a mixture of
styrene and acrylonitrile in the ratio 75:25 for a further 4 hours. The
product was then precipitated from the dispersion with a calcium chloride
solution at 95.degree. C. and was separated off, washed with water and
dried in a stream of hot air. The degree of grafting of the graft
copolymer was found to be 35%; the median particle size of the latex was
510 nm.
The following graft copolymer was prepared as product B-2:
1.5 parts of a poly(butyl acrylate) latex were mixed with 50 parts of water
and 0.1 part of potassium persulfate and then, over the course of 3 hours,
on the one hand a mixture of 43 parts of butyl acrylate, 6 parts of
polymerizable phosphate of the formula Ia and 1 part of tricyclodecenyl
acrylate, and on the other hand a solution of 0.5 part of the sodium salt
of a C.sub.12 -C.sub.18 -paraffinsulfonic acid in 25 parts of water were
run in at 60.degree. C. Polymerization was continued for 2 hours after the
addition was complete. The resulting latex of the crosslinked poly(butyl
acrylate) had a solids content of 40%. The median particle size (based on
weight) of the latex was found to be 430 nm. The particle size
distribution was narrow (Q=0.1).
150 parts of this latex were mixed with 20 parts of styrene and 60 parts of
water and stirred while a further 0.03 part of potassium persulfate and
0.05 part of lauryl peroxide were added, and then the mixture was heated
at 65.degree. C. for 3 hours. The dispersion obtained from this graft
copolymerization was then polymerized with 20 parts of a mixture of
styrene and acrylonitrile in the ratio 75:25 for a further 4 hours. The
product was then precipitated from the dispersion with a calcium chloride
solution at 95.degree. C. and was separated off, washed with water and
dried in a stream of hot air. The degree of grafting of the graft
copolymer was found to be 35%; the median particle size of the latex was
500 rm.
The following graft copolymer was prepared as product B-3:
1.5 parts of a poly(butyl acrylate) were mixed with 50 parts of water and
0.1 part of potassium persulfate and then, over the course of 3 hours, on
the one hand a mixture of 37 parts of butyl acrylate, 12 parts of
polymerizable phosphate of the formula (Ia) and 1 part of tricyclodecenyl
acrylate, and on the other hand a solution of 0.5 part of the sodium salt
of a C.sub.12 -C.sub.18 -paraffinsulfonic acid in 25 parts of water were
run in at 60.degree. C. Polymerization was continued for 2 hours after the
addition was complete. The resulting latex of crosslinked poly(butyl
acrylate) had a solids content of 40%. The median particle size (based on
weight) of the latex was found to be 430 nm. The particle size
distribution was narrow (Q=0.1).
150 parts of this latex were mixed with 20 parts of styrene and 60 parts of
water and stirred while a further 0.03 part of potassium persulfate and
0.05 part of lauryl peroxide were added, and then the mixture was heated
at 65.degree. C. for 3 hours. The dispersion obtained from this graft
copolymerization was then polymerized with 20 parts of a mixture of
styrene and acrylonitrile in the ratio 75:25 for a further 4 hours. The
product was then precipitated from the dispersion with a calcium chloride
solution at 95.degree. C. and was separated off, washed with water and
dried in a stream of hot air. The degree of grafting of the graft
copolymer was found to be 35%; the median particle size of the latex was
500 nm.
Component C
A continuous solution polymerization by a process as described, for
example, in the Kunststoff-Handbuch, Vieweg-Daumiller, Volume V,
(Polystyrene), Carl-HanserVerlag, Munich 1969, page 124, lines 12 et seq.,
was used to prepare the following copolymer:
SAN (styrene-acrylonitrile copolymer) with a S:AN ratio of 81:19 (% by
weight) and a viscosity number VN of 100 ml/g.
Component D: Triphenyl phosphate
Component E: PTFE dispersion with a solids content of 60% by weight and a
particle size of 0.23 mm (DuPont, Type 30 N). The density of the sintered
solid is 2.3 g/cm.sup.3.
TABLE
__________________________________________________________________________
Formul-
ation
1 2 3 4 5 6 7 8 9 10
__________________________________________________________________________
A 64.65
64.65
64.65
64.65
64.65
64.65
64.65
64.65
64.65
64.65
B1 8 8 -- -- -- -- 8 -- 8 --
B2 -- -- 8 8 8 8 -- -- -- --
B3 -- -- -- -- -- -- 8 8 8 8
C 15 16 15 16 17 18 15 16 17 18
D 12 11 12 11 10 9 12 11 10 9
E 0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
0.35
MFI 59 53 121 109 90 78 170 152 137 107
Vicat
86.2
90.5
84.7
87.8
91.1
94.6
83.5
85.7
89.3
92.4
UL 94
V-0
V-1
V-0 V-0 V-1
V-1
V-0 V-0 V-0 V-2
__________________________________________________________________________
Top